Cars and other vehicles may be the first thing that springs to mind at the mention of fuel cells, but the technology can of course also be used for plenty of other devices big and small, and a team of researchers at Carnegie Mellon University are now looking to take them to a few new places that haven't been possible so far. To that end, they've developed what they claim is the world's smallest biological fuel cell, which is the size of a single human hair and "generates energy from the metabolism of bacteria on thin gold plates in micro-manufactured channels." That, they say, could make it ideal for use in places like deep ocean environments where batteries are impractical -- or possibly in electronic devices with some further refinements, where they could potentially store more energy than traditional batteries in the same space. The university's full press release is after the break.

PITTSBURGH-Carnegie Mellon University's Kelvin B. Gregory and Philip R. LeDuc have created the world's smallest fuel cell powered by bacteria. Future versions of the biology-powered fuel cell could be used for self-powered sensing devices in remote locations where batteries are impractical, such as deep ocean or geological environments.

"We have developed a biological fuel cell which uses microbial electricity generation enabled by microfluidic flow control to produce power," said Gregory, an assistant professor of civil and environmental engineering at Carnegie Mellon.

The new device, the size of a single strand of human hair, generates energy from the metabolism of bacteria on thin gold plates in micro-manufactured channels. The fuel cell recruits necessary bacteria to create a biofilm that utilizes natural organic compounds as fuel to generate power.

Future versions of this tiny bacteria-powered fuel cell could replace batteries in microelectronic devices. While batteries are used to do that today, fuel cells are able to store more energy in the same space.

"Our biology-powered fuel cell could be less costly to make and more easily deployed in remote areas than conventional batteries that require invasive maintenance," said LeDuc, an associate professor of mechanical engineering with courtesy appointments in Biomedical Engineering, Biological Sciences and Computational Biology departments.

Both researchers report that the evolution of microbial electricity generation is motivated by the potential for renewable energy sources and waste biomass to serve as a fuel for large-scale electricity generation.

"Our work also is prompted by increased interest in improved battery technology for small scale electronic devices and sensors," Gregory said.